These rumble strips only “mumble,” but their intent is clear, says Michigan DOT

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Updated Jun 8, 2020
An example of a mumble strip, or sinusoidal strip. Credit: Minnesota DOTAn example of a mumble strip, or sinusoidal strip. Credit: Minnesota DOT

The Michigan Department of Transportation plans to spend the month of June rolling out a safety measure intended to keep drivers from inadvertently careening out of their lanes, while also not annoying nearby residents as much.

MDOT reports it will spend about $1 million installing 383 miles of sinusoidal corrugations, or “mumble strips,” on asphalt shoulders along rural state highways.

A more subdued relative to the rumble strip, their intent is the same. But they are designed for narrower asphalt roads and to be quieter, to create less disturbance to nearby residents.

A traditional rumble strip. Credit: Minnesota DOTA traditional rumble strip. Credit: Minnesota DOT

“Rumble strips are a proven countermeasure to lane departure crashes brought on by driver drowsiness, distraction or inattention,” MDOT says. “Mumble strips, pioneered in Minnesota and tested over the past few years on several stretches of highway in the Upper Peninsula, can be installed on narrower asphalt shoulders and are designed to create less noise outside of the vehicle but have the same effect of alerting the driver.”

Check out this video below in comparing the rumble and mumble strip:

The Minnesota DOT began testing the strips for years and performed a widespread installment of mumble strips in 2018 as a way to increase safety yet reduce road noise. The strips were used to alert drivers to traffic intersections.

The Michigan DOT says the variable-depth strips will be installed via mobile operation on shoulders 6 feet wide or narrower. The following counties will get the strips: Alger, Baraga, Chippewa, Delta, Gogebic, Houghton, Luce, Mackinac, Marquette, Menominee and Ontonagon.